Question

我试图编写一个方法，用一个句子中的单词，列出不同的单词，以及它们出现的次数，但我无法让它工作。

这是我到目前为止所做的：

var wordsArr = ['one', 'fish', 'two', 'fish', 'red', 'fish', 'blue', 'fish']
var wordsObj = {};
for (var i = 0; i < wordsArr.length; i++) {
   var counter = 0;
   wordsObj.wordArr[i] = counter++;
}
return wordsObj;

最后，我希望看到这一点：

{ one : 1, fish : 4, two : 1, red : 1, blue : 1 }

我的控制台告诉我，

＆＃39;未捕获的TypeError：无法设置属性＆＃39; 0＆＃39;未定义＆＃39;

我认为undefined指的是counter变量。我已经尝试在循环内部和之前声明这一点（如0），但这不起作用。

是否将wordsArr[i]作为字符串返回，因此未正确设置为wordsObj的属性？

如果有人能告诉我哪里出错了，我会很感激。提前谢谢。

Answer 1

该属性将跟踪计数的实例，因此您不需要counter变量：

var wordsArr = ['one', 'fish', 'two', 'fish', 'red', 'fish', 'blue', 'fish']
var wordsObj = {};
for (var i = 0; i < wordsArr.length; i++) {
   //var counter = 0;
   wordsObj[wordsArr[i]] = ( wordsObj[wordsArr[i]] || 0 ) + 1;
}
console.log( wordsObj );

除了你有一些轻微的语法错误之外......

Answer 2

另一种方法可以是

＆＃13;

var longText = "These excellant intentions were strengthed when he enterd the Father Superior's diniing-room, though, stricttly speakin, it was not a dining-room, for the Father Superior had only two rooms alltogether; they were, however, much larger and more comfortable than Father Zossima's. But tehre was was no great luxury about the furnishng of these rooms eithar. The furniture was of mohogany, covered with leather, in the old-fashionned style of 1820 the floor was not even stained, but evreything was shining with cleanlyness, and there were many chioce flowers in the windows; the most sumptuous thing in the room at the moment was, of course, the beatifuly decorated table. The cloth was clean, the service shone; there were three kinds of well-baked bread, two bottles of wine, two of excellent mead, and a large glass jug of kvas -- both the latter made in the monastery, and famous in the neigborhood. There was no vodka. Rakitin related afterwards that there were five dishes: fish-suop made of sterlets, served with little fish paties; then boiled fish served in a spesial way; then salmon cutlets, ice pudding and compote, and finally, blanc-mange. Rakitin found out about all these good things, for he could not resist peeping into the kitchen, where he already had a footing. He had a footting everywhere, and got informaiton about everything. He was of an uneasy and envious temper. He was well aware of his own considerable abilities, and nervously exaggerated them in his self-conceit. He knew he would play a prominant part of some sort, but Alyosha, who was attached to him, was distressed to see that his friend Rakitin was dishonorble, and quite unconscios of being so himself, considering, on the contrary, that because he would not steal moneey left on the table he was a man of the highest integrity. Neither Alyosha nor anyone else could have infleunced him in that.",
       words = longText.split(" ").map(w => w.toLowerCase()),
   wordCount = words.reduce((p,c) => (p[c] === void 0 ? p[c] = 1 : ++p[c],p),{});
console.log(wordCount);

＆＃13;

将数组元素指定为对象属性，使用＆＃39; counter＆＃39;值

2 个答案: